Antibacterial composition containing diastereoisomers of 1-(p-methylsul-fonylphenyl)-2-(alpha, alpha-dichlo-roacetamido)-1, 3-propanediol



United States Patent 0,

ANTIBACTERIAL COMPOSITION CONTAINING DIASTEREOISOMERS OF 1-(p -METHYLSUL- FONYLPHENYL) 2 (ALPHA,ALPHA-DICHLO- ROACETAMIDO)-1,3-I'ROPANEDIOL Robert P. Pirou,Wilmington',f Del.,.assignor to E. 2. du Pont de Nemours and Company, Wilmington, Del., a corporation otDelaware I No Drawing. Application May 10, 1954, Serial No. 428,839

1 Claim. (Cl. 26(i562) This invention relates to an antibacterial composition and more particularly to a complex compound consisting of two parts by weight of dl-threo-l-(p-methylsulfonylphenyl) 2 (alpha,alpha dichloroacetamido) 1,3-propanediol and one part by weight of dl-erythro-l- (p methylsulfonylphenyl) 2 (alpha,alpha-dichloroacetamido)-1-,3-propanediol.

1 (p methylsulfonylphenyl) 2 .(alpha,alpha dichloroacetamido)-1,3-propanediol is described and claimed in the copending U. S. application of Walter A. Gregory, Serial No. 257,986, filed November 23, 1951. The antibacterial activity of the d-threo and the dl-threo forms of 1-(p-methylsulfonylphenyl)-2-(alpha,alphadichloroacetamido)-1,3-propanediol is reported by Suter et al. in the J. Am. Chem. Soc. 74, 5475 (1952), and 75, 4330(1953).

It is known that the erythro form of l-(p-methylsulfonylphenyl) 2 (alpha,alpha dichloroacetamido) 1,3-propanediol has substantially less activity than the corresponding threo form against such microorganisms as, for example, Brucella abortus, Salmonella typhrimurium, Salmonella gallinarum, Streptococcus agalactiae, Escherichia coli, Micrococcus pyogenes, Pasturella avicia'a, and Klebsiella pneumoniae.

Surprisingly, I have now found that my novel complex compound containing one-third part of the inactive erythro form has on a weight basis equivalent antibacterial activity as the separate threo form. While this 33%; per cent gain is biological activity on a weight basis is not fully understood, it is believed that it is a synergistic phenomenon.

The intramolecular composition of my invention is a white solid, melting sharply at 168-168.5 C. It has a solubility in water at 26 C. of 1.92 grams per liter. This is in contrast to (1) the dl-threo form which melts at 180-181 C. and which has a solubility in water at 26 of 1.185 grams per liter, and (2) the dl-erythro form which melts at l99l99.5 C.

The complex compound of the present invention can be prepared from alpha,alpha-dichloro-N-[-Z-hydroxy- 1-(p-methylsulfonylbenzoyl)ethyl]acetamide using sodium borohydride. This reduction is effected in an aqueous medium or in the presence of a lower aliphatic alcohol, such as, for instance, methanol, ethanol, isopropanol, or butanol. The reaction can also be carried out in dimethylformamide, and the like.

A mixture of isomers of dl-l-(p-methylsulfonylphenyl 2 (alpha,alpha dichloroacetamido) 1,3 propanediol are obtained from the sodium borohydride reduction step. The mixture is fractionated by crystallization using as a solvent boiling nitromethane. Two distinct products are obtained. One is a less soluble fraction, melting at 199-200 C. after purification, and consists of erythro-dl-l-(p-methylsulfonylphenyl)-2-(alpha,alpha-dichloroacetamido)-1,3-propanediol. A more soluble fraction, which melts without purification at nel.

ice;

166-169" C. and at"168-168'.5" C. followingupurifiew tion. Y Alpha,alpha dichloro N-- [2 --hydroxyl 1 (p methylsulfonylbenzoyl)ethyl]acetamide can be readily prepared as described in the aforementioned-Gregory application from alpha,alpha-dic':hloro-N-'(p-metliylsul fonylphenacyDacetamide by aldol type of condensation in an'alcoholic mediumusing aqueous formaldehyde and sodium bicarbonate. The synthesis of'thissketon'e is also described in the aforementioned publication-of Suteriet 21;, J. Am. ChemzSoc. 75,433'0-(1953):

The complex compound of my invention can also be prepared by fractional crystallization of synthetic mixtures of threoand erythro-1-(p-methylsulfonylphenyl)- 2 (alpha,alpha dichloroacetamido) 1,3 propanediol. When two parts by weight of threo and one part of erythro compound are dissolved in water, the complex compound of the invention crystallizes from the solution in excellent yields.

In order to better understand this invention, reference should be had to the following illustrative example:

Example To a slurry of 88.5 grams of alpha,alpha-dichloro- N [2 hydroxyl 1 (p methylsulfonylbenzoyD- ethyllacetamide in 500 ml. of water, there is added dropwise' 12.5 grams of sodium borohydride in 125 ml. water over a period of about fifteen minutes. During this addition the temperature of the reaction mixture is maintained at from about 25 to 30 C. The reaction mixture is stirred for about one hour.

The progress of the reaction is followed by withdrawing aliquots from the mixture from time to time and determining their melting ranges. When the lower lim it of the melting range is l62165 C., the reaction is stopped by acidification with a mineral acid.

Fifty-eight ml. of 5 N hydrochloric acid is' added dropwise to the reaction mixture over a 30 minute period. The mixture is externally cooled and about 5 ml. of Antifoam A in ethanol is added to decrease foam- The precipitated reaction product is collected by filtration of the mixture, washed twice with 100 ml. portions of water, and air dried to give 86 grams, M. P. 162-177 C.

grams of the product melting 162-177 C. is added to 400 ml. boiling nitromethane. After 5 minutes, the mixture is filtered thru a heated glass fun- The insoluble material is collected, washed with ether and dried to 15.8 grams of impure erythro isomer, M. P. 191194 C. Recrystallization of this impure material from acetonitrile raised the melting-point to 197-198" C.

The nitromethane filtrate is cooled, and crystals form. These are collected, ether-washed and air dried to give 53 grams of material melting 164.5178C.'

ing chemical analysis: Calcd. for C12H15CI2NO5S: C,

40.4%; H, 4.21; Cl, 19.95; N, 3.93; S, 8.98. Found: C, 40.8; H, 4.32; Cl, 19.71; N, 4.05; S, 8.98.

In boiling nitromethane, the complex compound which consists of two parts of threo isomer and one part erythro isomer has a solubility which is about twice that Patented Dec.16,. 1'955 About 19 of the. dl-threo-l-(p-methylsulfonylphenyl)-2-(a1pha,alpha-dichloroacetamido)-1,3-propanediol. The point of the complex compound is depressed by the starting ketone to 140-142 C. The melting ranges of the complex compound with the individual erythro' and three forms are as follows:

a. Mixed with threo form 1665-170 C.

b. Mixed with erythro form 168187 C.

.The constituents of my intramolecular composition cannot be separated by known crystallization techniques. Crystallizations of the complex compound from water acetonitrile, ethanol or nitromethane do not change its melting point. I

I claim:

A complex compound consisting essentially of two melting ill References Cited in the file of this patent UNITED STATES PATENTS Long et al. June 15, 1954 Long Aug. 24, 1954 OTHER REFERENCES Suter et al.: J. Am. Chem. Soc., vol. 75, September 5, 1953, pp. 4330-33. (Received May 15, 1953.) 

